Tracking devices are commonly used to track the position of vehicles, aircraft, vessels and the like. Typically, a tracking device comprises a GPS receiver that receives signals from a GPS satellite network. From the signals, the tracking device can calculate its location, and therefore the current location of the vehicle, vessel or aircraft in which it is installed. The device can have an output that indicates to a user the current position of the device and also historical position information.
The device may also transmit position information via a mobile telephone network or satellite based network to a monitoring system. The monitoring system itself can receive position information from a range of tracking devices installed on vehicles, vessels and/or aircraft. The monitoring system can log the information to enable monitoring of the position of one or more vehicles, vessels and aircraft at a central location. The information can be accessed via user directly at the monitoring location, or perhaps via a website.
It is an object of the present invention to provide apparatus, system or a method that allows for monitoring of an aircraft.
In a first aspect the invention may broadly be said to consist of an aircraft monitoring system comprising a computer system and a receiver for receiving tracking data from a tracking device associated with an aircraft, the monitoring system having an active tracking mode in which the computer system is configured to determine a condition indicative of an aircraft incident based on the absence of received tracking data, wherein the monitoring system is automatically triggered into the active tracking mode when a signal is received from the aircraft indicating the aircraft has taken-off.
In one embodiment of the first aspect the signal is received from the aircraft after an apparatus on the aircraft determines take-off from any one or more of a change in aircraft speed, a change in aircraft altitude, or a change in distance traveled by the aircraft.
Preferably the apparatus is the tracking device and determines take-off from any one or more of a change in aircraft speed, a change in aircraft altitude or a change in distance traveled by the aircraft.
Alternatively the apparatus obtains data from sensors on the aircraft indicative of or from which can be determined any one or more of a change in aircraft speed, a change in aircraft altitude, or a change in distance traveled by the aircraft or other parameter indicating aircraft take-off.
In a second embodiment of the first aspect the signal contains data indicative of or from which can be determined any one or more of a change in aircraft speed, a change in aircraft altitude, or a change in distance traveled by the aircraft indicating aircraft take-off.
In a third embodiment of the first aspect the signal is received from the aircraft after an undercarriage position sensor triggers to indicate aircraft take-off.
Preferably in any one of the embodiments of the first aspect the condition indicative of an incident is determined based on the received tracking data.
Preferably the condition indicative of an incident is based on the absence of tracking data received from the tracking device in accordance with a transmission regime.
Preferably the tracking data comprises at least position information of the tracking device.
Preferably the aircraft monitoring system further comprises a tracking device in the aircraft, wherein the tracking device comprises:                a positioning system for determining position information of the tracking device and/or the aircraft, and        a transmitter for transmitting the position information to the monitoring system.        
Preferably the position system is a Global Positioning System (GPS) comprising a GPS receiver and antenna for receiving position information from a GPS satellite.
Preferably upon determining a condition indicative of an incident in the active tracking mode, the monitoring system is adapted to provide an alert.
In a second aspect the invention may broadly be said to consist of a tracking device for installation in an aircraft and for use with an aircraft monitoring system, the apparatus comprising:                a receiver for receiving GPS signals,        a processor for generating tracking data from the GPS signals and/or other input information, and        a transmitter for transmitting to an aircraft monitoring system the tracking data and/or a signal indicating take-off to trigger the aircraft monitoring system into an active tracking mode in which the monitoring system is configured to determine a condition indicative of an aircraft incident based on the absence of received tracking data.        
Preferably the processor determines take-off from any one or more of a change in aircraft speed, a change in aircraft altitude, and a change in distance traveled by the aircraft from the tracking data and generates the signal in response.
Preferably the processor receives data from one or more sensors and determines take-off from any one or more of a change in aircraft speed, a change in aircraft altitude, or a change in distance traveled by the aircraft from the sensor data and generates the signal in response.
In this specification where reference has been made to patent specifications, other external documents, or other sources of information, this is generally for the purpose of providing a context for discussing the features of the invention. Unless specifically stated otherwise, reference to such external documents is not to be construed as an admission that such documents, or such sources of information, in any jurisdiction, are prior art, or form part of the common general knowledge in the art.
The term “comprising” as used in this specification means “consisting at least in part of”. Related terms such as “comprise” and “comprised” are to be interpreted in the same manner.
To those skilled in the art to which the invention relates, many changes in construction and widely differing embodiments and applications of the invention will suggest themselves without departing from the scope of the invention as defined in the appended claims. The disclosures and the descriptions herein are purely illustrative and are not intended to be in any sense limiting.